.nav {
  display: flex;
  position: fixed;
  align-items: center;
  justify-content: center;
  right: 0;
  top: 50vh;
  height: 100px;
  width: 50px;
  cursor: pointer;
  transition: background .3s;

  img {
    height: 40px;
    transform: translateX(4px);
    opacity: .5;
    transition: opacity .3s;
  }

  &:hover {
    background-color: rgba(255,255,255, .2);

    img {
      opacity: 1;
    }
  }
}

.nav.back {
  right: auto;
  left: 0;

  img {
    transform: rotate(180deg);
  }
}
